1. Field of the Invention
The present invention relates generally to a probe module for a vertical probe card and more particularly, to a guide plate for aligning, guiding and supporting probes, which is provided with a current-diverting path to the probes, and a probe module using the guide plate.
2. Description of the Related Art
FIG. 1 schematically shows a conventional probe module 10 for use in a vertical probe card, comprising an upper guide plate 11, namely an upper die, a lower guide plate 12, namely a lower die, and a plurality of probes 13. The probes 13 each have a head 132 inserted through one of upper guide holes 112 provided at the upper guide plate 11, and a tip 134 inserted through one of lower guide holes 122 provided at the lower guide plate 12. When the tips 134 of the probes 13 contact the contact pads of the device under test (hereinafter referred to as “DUT”), a reaction force generated from the DUT is applied to the tips 134 of the probes 13 and urges the tips 134 of the probes 13 to slidably move back relative to the lower guide holes 122 to further result in deformation of the bodies 136 of the probes 13. By this mechanism, a stable contact force acting on the DUT is provided by the tips 134 of the probes 13 for allowing the test signal generated from a tester to be reliably transmitted to the DUT, and a buffering effect achieved by the deformation of the bodies 136 of the probes 13 is simultaneously provided upon probing the DUT for protecting the DUT or the probes 13.
In order to meet the product requirements of size reduction and multifunction, the pitch between two adjacent contact pads of the device under test has become smaller and smaller; under this circumstance, the probe diameter needs to be minimized for facilitating positive contact of the contact pads of the DUT having a downsized pitch. However, once the probe diameter is reduced, the probe 13, especially the buckling body 136 of the probe 13, may easily burn out due to an unexpected excessive instantaneous current running therethrough. If this happens, the damaged probe 13 has to be repaired or exchanged, causing a delay in the testing schedule.
To deserve to be mentioned, not only the probe module 10 shown in FIG. 1 but also a probe module having a guide plate for aligning, guiding and supporting the probes, such as the probe modules disclosed in U.S. Pat. No. 4,622,514 and U.S. Pat. No. 7,417,447, may have the above-mentioned problem, i.e. the slim probe tends to burn out due to instantaneous overcurrent.